Diagonal brace mounting for tiltable bulldozer blade



March 20, 1962 R. K. LIESS 3,025,620

DIAGONAL BRACE MOUNTING FOR TILTABLE BULLDOZER BLADE Filed Oct. 17, 19602 Sheets-Sheet 1 IN VEN TOR.

Richard K. Liess TOENEYS March 20, 1962 R. K. LIESS 3,025,620

DIAGONAL BRACE MOUNTING FOR TILTABLE BULLDOZER BLADE Filed Oct. 17, 19602 Sheets-Sheet 2 IN V EN TOR.

Richard K. Liess Y B W Mi A IOBNEYS 3,025,620 DIAGONAL BRACE MOUNTINGFOR TILTABLE BULLDUZER BLADE Richard K. Liess, .loliet, Ill., assignorto Caterpillar Tractor Co., Peoria, ill, a corporation of \CaliforniaFiled Oct. 17, 1966, Ser. No. 63,116 4 Claims. (Cl. 37144) Thisinvention relates to bulldozers and particularly to means for bracingthe blades of tiltable bulldozers to prevent damage resulting in partfrom stresses which are set up when a blade is adjusted to its tiltposition.

The application relates to the correction of difficulties which aredescribed in detail in a copending application of Robert W. Lichti forDiagonal Brace Mounting for Bulldozer Blades, Serial No. 21,501, filedApril 11, 1960. As described in said copending application, theconventional tiltable bulldozer is subjected to excessive compressivestresses in its diagonal braces when it is moved to a tilt positionwhich stresses are reacted by the push arms and impart thereto bendingforces often of sulficient magnitude to result in breakage of an arm.

It is the object of the present invention to provide a mounting for thediagonal braces of a tiltable type bulldozer through which the forcesabove referred to are materially reduced and through which many of thestresses to which bulldozer structures are subjected are eliminated.

Further and more specific objects and advantages of the invention aremade apparent in the following specification by reference to theaccompanying drawings.

In the drawings:

FIG. 1 is a schematic plan view of a tractor with a bulldozer embodyingthe present invention;

FIG. 2 is a perspective view showing the rear side of the bulldozerblade with the diagonal braces of the present invention and also showingthe tilt braces and portions of the push arms;

FIG. 3 is a view in side elevation of the bulldozer with portions shownin section;

FIG. 4 is a fragmentary sectional view taken on the line IV-IV of FIG.3; and

FIG. 5 is a schematic plan view of a tractor with a conventionalbulldozer with the forces imposed on the diagonal braces and push armsindicated by arrows.

In FIG. 1 of the drawings, a tractor, generally indicated at 10, isshown as provided with a bulldozer blade 11 carried at the forward endof a pair of push arms 12. At their rearward ends the push arms areconnected in a conventional manner to the truck frames of the tractor asby ball and socket type joints shown at 13. The bulldozer blade ispivotally connected to the forward ends of the push arms as by hingeconnections 15 and held in an erect position by braces known as tiltbraces shown at 16 and 17 (see FIG. 2). The tilt brace 17 includesadjustable means which may be in the form of a conventional extensiblehydraulic cylinder 18. The tilt braces are connected as by pivot pinsand brackets 19 to the tops of the push arms and ball and socket joints24 to the back of the blade adjacent its upper edge. A pair of diagonalbraces 22 and 23 extend between the inner sides of the push arms towhich they are pivotally connected with brackets shown at 24 and thesediagonal braces are, in conventional bulldozers, usually connecteddirectly to the back of the blade by a ball and socket joint such asillustrated at 25 in FIG. 5 wherein a conventional bulldozer is shown.Conventional lift jacks are shown at 26 as extending between the tractorand bulldozer blade to which they are connected through brackets 27fixed to the back of the blade. The present invention is also applicableto bulldozers wherein cable controls are employed in place of the liftjacks 26.

3,625,629 Patented Mar. 20, 1962 To effect tilting of the blade as forexample toward the right, the tilt brace 17 is lengthened by extensionof the cylinder 18, fluid to which is supplied in a conventional manner.Due to the bracing illustrated and above described, this lengthening ofthe tilt brace 17 raises the left end of the blade as well as theforward end of the push arm and imposes stresses on the diagonal bracesand the push arms which are indicated by arrows in FIG. 5 of thedrawings. In FIG. 5, the left side of the blade has been raised and bothdiagonal braces are placed in compression as indicated by arrows a thusimposing a bending stress on each of the push arms which are shown at12' in FIG. 5. When this condition exists and the blade 11' is subjectedto a side thrust as indicated by the arrow 11, the structure tends tocollapse and a severe bending force is reacted by one of the push arms12' at the point indicated by the arrow c. This results from theaddition of compressive stresses, arrow d, to one of the diagonal braceswhile the stress on the other is relieved by the side thrust whichimparts tension to the opposite diagonal brace as represented by thearrow e.

Through the present invention as through the invention described in thecopending application hereinabove referred to, the compressive stress inthe diagonal braces and the bending stress on the push arms is reducedand the compressive stresses upon the diagonal braces are distributedbetween them. This is accomplished as best shown in FIGS. 2, 3 and 4 byconnecting the inner ends of the diagonal braces 22 and 23 together in amanner which permits slight twisting movement of one with respect to theother and by connecting them to the back of the bulldozer blade 11 bymeans which permits them to move forwardly with respect to the blade.These means comprise a pair of vertically spaced plates 33!) secured asby welding to the rear face of the bulldozer blade and slotted toreceive the squared end 31 of a pin to enable it to slide in alongitudinal direction with respect to the tractor. The diagonal brace22 is provided with a bifurcated end 32 which embraces the pin at spacedpoints through bearing caps best shown at 33 in FIG. 4. A sphericalportion 35 is provided centrally of the pin and between the spaced endsof the brace 22 and this spherical portion is embraced by a sphericalsocket formed between the end of the diagonal brace 23 and a cap 36thereon. This end of the brace 23 fits loosely in the bifurcated end ofthe brace 22 as shown in FIG, 3 to permit twisting movement of thebraces relative to each other while both are capable of limited rotationabout the axis of the pin and forward and rearward movement relative tothe blade.

With the construction described, upon tilting of the blade by elongationof the tilt brace 17, both diagonal braces tend to be compressed asrepresented by the arrows a in FIG. 5. However, due to their ability toslide forwardly in the slots of the plates 30, they are relieved of thecompressive stress and the application of excessive forces which tend tobend the push arms: outwardly is eliminated. When a side thrust isimparted to the blade as represented by the arrow 0 in FIG. 5 whether ornot the blade is tilted, the tensile stress represented by arrow 6" onone brace and the compressive stress represented by the arrow d on theopposite brace are equalized because the stress of each diagonal braceis transmitted to the other through the articulated connection of theforward ends of the braces.

I claim:

1. In a bulldozer blade mounting which comprises push arms secured tothe blade, tilt braces extending upwardly between the tops of the pusharms and the blade, and diagonal braces extending inwardly from theinner sides of the push arms to the blade and means to adjust the lengthof at least one of said tilt braces to efiect tilting of the blade,means to reduce stresses set up in the mounting upon such tiltingincluding, a universal connection between the inner ends of saiddiagonal braces connecting them to each other, guid means secured to therear of the blade, and means connecting the inner ends of the diagonalbraces to said guide means for limited movement in a direction normal tothe blade.

2. In a bulldozer blade mounting which comprises push arms secured tothe blade, tilt braces extending upwardly between the tops of the pusharms and the blade, and diagonal braces extending inwardly from theinner sides of the push arms to the blade and means to adjust the lengthof at least one of said tilt braces to effect tilting of the blade,means to reduce stresses set up in the mounting upon such tiltingincluding, a vertically disposed pin hingedly connecting the inner endsof said diagonal braces to each other, and means on the rear of theblade embracing said pin to guide it for movement in a direction normalto the blade.

3. In a bulldozer blade mounting which comprises push arms secured tothe blade, tilt braces extending upwardly between the tops of the pusharms and the blade, and diagonal braces extending inwardly from theinner sides of the push arms to the blade and means to adjust the lengthof at least one of said tilt braces to effect tilting of the blade,means to reduce stresses set up in the mounting upon such tiltingincluding, a vertically disposed pin hingedly connecting the inner endsof said diagonal braces to each other, and means on the rear of 4 theblade embracing said pin to guide it for movement in a direction normalto the blade, said pin having an enlarged portion of spherical contourand one of said diagonal braces having a socket of complementary contourembracing said enlargement to permit limited universal movement betweenthe diagonal braces.

4. In a bulldozer blade mounting which comprises push arms secured tothe blade, tilt braces extending upwardly between the tops of the Pusharms and the blade, and diagonal braces extending inwardly from theinner sides of the push arms to the blade and means to adjust the lengthof at least one of said til-t braces to effect tilting of the blade,means to reduce stresses set up in the mounting upon such tiltingincluding, a vertically disposed pin hingedly connecting the inner endsof said diagonal braces to each other, and means on the rear of theblade embracing said pin to guide it for movement in a direction normalto the blade, said means on the rear of the blade comprising a pair ofvertically spaced plates having rectangular slots therein, and said pinhaving rectangular enlarged portions slidably guided in said slots.

References Cited in the file of this patent UNITED STATES PATENTS2,232,672 Low Feb. 18, 1941 2,764,824 Kepner Oct. 2, 1956 2,817,168Mullin Dec. 24, 1957 2,942,363 Long June 28, 1960

